So a title that would make sense to people not familiar with Discord terminology could be:
> How Discord Serves 15M Members of a Single Workspace
It's funny how in hindsight simple changes to major web applications have a major impact. I remember, Tumblr used to show you every statistic about your blog on the dashboard, that meant every single time someone hit the front-page they had to query the latest data to show you your follower count. Sometime after they removed it from the Dashboard, I noticed Tumblr went offline / down significantly less, I doubt that was the only optimization they did, but I presume they did loads of optimizations to their platform at the time.
When you first get stuff working doing a query is easier and faster. At some point you remove it and move to counters that are updated via your data pipe.
[0] https://discord.com/blog/maxjourney-pushing-discords-limits-...